Head Gasket Questions

[john84]

Hi All, Sorry to start another HG thread but couldn't quite find what i was looking for.

I'm putting a 7MGTE together at the mo and it has come to the moment i need to put the head on. The head i'm using has been skimmed by the previous owner who got bored of the project and i fully intend to check how much has been taken off.

So, onto choosing a HG.

I have a stock head gasket that came with my gasket set for the rebuild but from what i have read the normal practice is to upgrade to a MHG, however i also understand that the deck and the head surfaces have to be super smooth for the MHG to get a proper seal.

the deck has not been machined but is in what i would consider to be a good condition, would a stock head gasket give a more reliable seal in my case?


My power goals are modest, i'm running stock internals and will probably be going for a 57 trim ct26 with a hope for 300 - 350bhp at the crank in the future with app fueling mods. I will be using ARP studs.

of course price is always a factor and in the ideal world i would send it all to the machine shop, but this world isn't ideal.

My final question regards re-using MHG's, i Have a MHG from a 7MGTE that has seen around 20 miles and 4 psi. My natural reaction is to say it's fit for the bin, but some people have suggested otherwise to me.

Any thoughts on the subject would be great, John.

 

[MassSupra89]

A stock replacement will seal better if your deck surface is not smooth enough for a MHG. MHG's can be cleaned and re-used if it will still seal, and all holes/jackets are in good condition. Cometic MHG's are also more leniant on sealing and the surfaces don't have to be machined to such tight tolerances as other's. IMO you will be fine making 300hp on the stock gasket with ARP's for a long time.

 

[gaboonviper85]

I see alot of confusion in this thread...BOTH block AND head need to be decked to an RA spec desired from the headgasket mfg! If the head hasn't been decked then I'm 100% sure that the gasket surface is warped out of spec which can cause sealing issues with both type gaskets.

You can get away with useing the metal gasket again but it must be taken appart and cleaned with acetone or whatever...each and every layer needs cleaned and sprayed with permatex copper spray or the likes...

Good luck!

 

[MassSupra89]

In my post I was referring to RA, not warpage when I said deck surfaces. I agree both need to be refinished for a MHG but I brought my old 100k mile head to my machinist and he said it was straight and would do fine with just a cleaning and stock HG but I wanted to go with a stopper.

 

[RiyadYar]

i got my head resurfaced at a local machine shop but just cleaned up the block because its still in the car, would i be fine with a cometic headgasket or would you guys suggest felpro .. as i knw for mhg you should do both head and block

 

[Rennat]

ace at zankoku puts cometic's on EVERYTHINGGGGGG. you should see all of his projects that have cometics on them.

i wouldnt go with a felpro... its an OEM style gasket and wont stand up to any serious abuse...

and the cometic = titan mhg just FYI... but i would get a cometic if your not going to deck the block.

 

[RiyadYar]

sounds like the best option.. i know you can reuse a mhg with the copper spray ,,, is it the same case for cometic ?

 

[john84]

Many thanks for all the help guys, will be getting on with it this week :icon_bigg

 

[CajunKenny]

i Have a MHG from a 7MGTE that has seen around 20 miles and 4 psi.

4 psi?

 

[john84]

Yes 4psi, The turbo was not in great condition and there was a rather large boost leak.

 

[FullNelson]

I have the same problem. my machinist bacically insulted my HKS headgasket (not bead style). He decided to use a different style gasket with "SS combustion chamber seals". Anyone heard anything of this style HG?